Engines of many types are employed in a variety of applications, such as transportation and power generation. Such engines are typically controlled electronically, and employ various control components that are used to operate the engine, such as fuel injectors, crankcase ventilation valves, and engine monitoring sensors, which are electrically connected to an electronic control unit by a wiring harness. In some applications, the engine may be located in a potentially problematic environment, such as one containing contaminants and/or possibly flammable gas or vapor mixtures. In such environments, it is desirable to prevent the harness from being exposed to the environment in order to prevent damage to the wired connections to the control components, and to reduce the likelihood of an explosion being caused by an inadvertent spark in the wiring harness or at the electrical connections between the wiring harness and the control components, for example, due to a build up of dust or other debris causing a short circuit at the electrical connections. Various government regulations may require that the engine be certified in order to operate in such environments. However, typical wiring harnesses may not meet the certification requirements.